Vinyl or allyl salicylate-ethylene copolymers and chelates thereof



VINYL on ALLYL sArrcYrArn-nrnYLENE coronrrrnns .AND 'crmra'rns THEREOF C'arleton '1. Handy and HenrySJsRothr-ock, Wilmington,

DeL, assignors to E. I. rlu Pont de Nemours and Company, lit ilmulugton, DelL, a corporation of Delaware No Drawing. Application October 2, .1958

Serial No. 764,736

, 21 Claims; c1. 260- 62) This invention relates to a new class of polymeric materials. More particularly, it relates to new organic polymers containing chelate-forming structures and to the metal chelates of these'polymers. This application is a continuation-in-part of our application, Serial No. 511,780, filed May 27, 1955, now abandoned.

Crosslinked synthetic polymers in which the crosslinkages are provided by metal chelate groups have been SKQICS heretofore only superficially mentioned in the published literature. Recent work, however, such as that described in application Serial No. 535,520, filed September 20, 1955, has shown that chelate crosslinked polymers have many desirable properties, including high softening temperature, insolubility in or resistance to water and the common organic solvents, and resistance tolight and oxidation. This applicationmoreo-ver describesaprocess by which these polymers can beshapedinto. useful :st-rucltures such as films, sheets, and the-like.

Chelate crosslinked polymers are conveniently. .pre-. pared by controlled chelation of anorganic polymer-com taining a multiplicityof chelate-formingstructures, i.'e., ligand functions. However, not many such. chelateforming polymers, or polymeric polyligands, have been described in the chemical literature, and of those that are still further object is the preparation of new filaments. A

Other objects will "appear hereinafter.

These objects are accomplished by the present inven-;

tion of copolymers of ethylene with a monomeric chelateforming compound of the formula where n is a cardinal number from 0 to 1, said copolymers containing, by weight, from about 0.05% to about 50% of the polymerized chelate-forming compound and at least 50% polymerized ethylene. The invention also includes as new products the chelates of these copolymers with polyvalent metals.

' The new products of this invention are copolymers, of,

I the type llhate nted Am- 1- polymers containing at least. 50% ethylene and from about 0.05% to about 50% by weight of vinyl salicylatej or allyl salicylate. These copolymers therefore contain a multiplicity of recurring chelate-forming structures of the type -ortcH- in the'jcase of vinyl salicylate, or

in the case of allyl'sa'licylate. Such polymers are capable of forming with polyvalent metals chelated products which] are .crosslinked through the siX-membered chelate rings To illustr'ate, with a divalent metal Me and polymers containing vinyl salicylate units, the. resulting chelated polymer will be c'rosslinked through units. oi

Where. the ring arrows represent coordinate linkages. More complex spatial structures. are formed when the 5 chelating metal has a valence higher'than two.

"The linear, metal-free copolymers are prepared, ac-

cording to known methods, by polymerizing together in I copolymers may contain other polymerized vinyl mon0 methyl methacrylateand the-like in minor amounts, e.g. up to 20% by weight of the total polymerized materials.-

suitable proportions vinyl or allyl salicylate with ethylene. In addition to the two essential components, the

mers, e.g isobutylene, vinyl acetate, 1,3-butadiene,

Such minor amounts of other constituents, among which vinyl acetate is the preferred one, do not appreciably affeet the chelate-forming properties of the copolymer but vinyl s 'y at o a ly sa i y a e withf, hyue,sa e

may serve to improve desirable properties such as organic solvent solubility and pliability. However, it is undesirable to have present in the copolymer more than about 20% of such third components since, beyond this point,

the compositions tend to be undesirably less tough. and to become objectionably tacky and pressure-sensitive.

The, chelate crosslinked polymers which are also part ofthis invention arepreferably prepared by the process of application Serial No. 535,520,, already referred ;to.

. metal chelate.

This new process, which has been called transchelation, consists broadly in treating an organic compound (e.g., a polymer) containing a plurality of chelate-forming structures with a chelate of a polyvalent metal with a volatile chelating agent, i.e., a chelating agent boiling below 300 Chat 760 mm. pressure, and evaporating the volatile chelating agent, thereby leaving a polymer crosslinked through metal chelate groups. What takes place in this process is a ligand exchange, organic compounds containing chelating structures being termed ligands, that is, a transfer of the metal from the chelating structure of the volatile chelating agentto those of the non-volatile polyligand. When the number m of chelate-forming structures in the non-volatile polyligand and the principal valence n of the metal are each at least two and the sum of m and n is at least fiv'e, a chelated polymer is formed and crosslinking through chelate rings takes place between the polymer molecules.

The outstanding advantage of the transchelation process just described is that the non-volatile polyligand and the polyvalent metal chelate of a volatile chelating agent can be combined in intimate admixtures, such as homogeneous solutions, without precipitation of the crosslinked, chelated polymer. Thus, these intimate mixtures can be formed, stored and handled at will, and it is only on removal of the volatile'materials by evaporation that formation of the crosslinked polymer takes place. This is because an equilibrium between ligands and metal exists in the solutions, which is shifted, with formation of the chelate crosslinkedpolymer, only when the volatile ligand is removed.

When, as is normally the case, a shaped structure of the chelate crosslinked polymer is desired, the shaping is done essentially concurrently with the removal of the volatile chelating agent, e.g., by casting, extruding or pressing objects such as film, sheets, filaments, molded structures and the like, and completing the evaporation of the volatile materials as needed. In cases where the chelated composition is moldable at high temperatures, shaping may be accomplished subsequently to chelation.

The intimate mixture of the polymeric polyligand and metal chelate of a volatile chelating agent need not be a homogeneous solution at room temperature. It is only necessary that its components form a homogeneous system at the temperature at which the shaped object is being formed. Additional inert solvents are not essential but are often used to aid in forming a solution. It is often desirable to add to the mixture a small additional amount of a'volatile chelating agent, e.g.,- acetylacetone, as insurance against premature gelation of the chelate crosslinked polymer.

The relative proportions of polymeric polyligand and polyvalent metal chelate of a volatile chelating agent can be such that there is present the calculated quantity of metal sufiicient to chelate all the salicylate groups in the polyligand. Assuming complete chelation, this would yield, when the starting copolymer contains the maximum amount (50% by weight) of chelate-forming salicylate monomer, a chelated polymer containing about 0.15 gram atom of metal per 100 g. of polymer with divalent metals, and proportionately less with higher than divalent metals. However, in general, chelated polymers containing less than that amount of metal are preferred because of their greater flexibility and homogeneity. While the chelated polymers should contain at least 0.005 gram atom of metal per 100 grams of polymer weight to realize the benefits of crosslinking, it is preferred that they contain not more than 0.1, and still more preferably between about 0.01 and 0.06 gram atom of metal per 100 grams of polymer weight. The desired quantity of metal can be introduced either by reacting a polyligand containing relatively few salicylate groups with the calculated amount of metal chelate, or by reacting a polyligand richer in salicylate groups with less than the calculated amount of In addition to the transchelation method just described, which is illustrated in Examples XI-XX and XXII-XXIIII below, other methods can be used to chelate the ethylene/vinylor allyl salicylate copolymers. One of these methods, illustrated in Example XXI, involves an alcohol exchange, or acoholysis, process wherein the ethylene/salicylic ester copolymer is reacted with a polyvalent metal alcoholate of a volatile alkanol. What takes place is an alcohol exchange between the phenolic hydroxyls of the salicylic ester groups and the alkoxy groups of the metal alcoholate, with simultaneous formation of chelate rings, as depicted by the following equation, using vinyl salicylate unit and aluminum triethoxide as illustrative reactants:

where the dotted lines represent portions of chelate rings similar to the one shown. Again, with a polyvalent metal alcoholate and a polymer containing a multiplicity of salicylate units, crosslinking through chelate rings will take'place between the polymer chains. As inthe transchelation process, the relative proportions of polymeric polyligand and polyvalent metal alcoholate are so chosen that achelated polymer containing the amount of metal specified above is formed. This procedure differs from the transchelation method in that it is essentially an irreversible reaction and the chelate crosslinked polymer separates from the reaction mixture as an insoluble ma.- terial. However, and particularly if the reaction is carried out at elevated temperature, the chelate crosslinked polymer is sufficiently, plastic to permit its being milled and sheeted, or molded. Alternatively, the unchelated polymercan first be shaped into the desired structure, which is then immersed in a solution of the polyvalent metal'alkoxidein a suitable solvent, whereby chelation takes'place at least at the surface of the object being treated.

. Still another method of preparing chelate crosslinked polymers from the ethylene/vinylor allyl salicylate copolymers consists in treating the copolymer, preferably dissolved in a suitable solvent, with a polyvalent metal ion in the form of a metal salt or oxide, dissolved in an organic or organic-aqueous solvent such as methanol or methanol-water, or even in water. Preferably there is used a salt of a polyvalent metal with a weak acid, e.g., an acid having a dissociation contant below about l 10- forexample cupric acetate, ferric acetate, zinc propionate, aluminum acetate, etc. This procedure is less applicable to the preparation of shaped structures since the chelated polymer generally separates at once from the mixture as an insoluble preciptate. However, it is a convenient method for obtaining the chelated polymer in bulk form when this is desired.

The chelate crosslinked polymers obtained by any of the above-described methods are high softening and insoluble in the solvents in which the non-chelated polymers are soluble. They are, however, softened or even dissolved by chelating solvents.

The invention is illustrated in greater detail by the V examples below. The. monomeric vinyl salicylate and allyl salicylate. used in these examples can be as follows: V

Vinyl salicylate.-This material was prepared by a. modification of the general method described in U.S. Patent 2,299,862 for the preparation of vinylesters. In a typical run, 8600 g. (100 moles) of redistilled vinyl acetate, 3450 g. (25 moles) of salicyclic acid, 60 g. of mercuric acetate and 8.5 ml. of concentrated sulfuric acid were charged into a stirred kettle. The resulting slurry was stirred at 25 C. for a total of live days. The excess salicyclic acid was removed by filt'ration, and 100g. of sodium acetate was added'to the filtrateand stirred for onehour to neutralize the catalyst. The excess vinyl acetate was then removed at 25 C. under reduced pressure. The residue was again filtered. The combined solids were washed with benzene and the filtrates were combined and distilled rapidly under reduced pressure through a short column. 1 The fraction boiling between 62 C.85 C; at 3 mm. pressure (839 g.) was collected (some gas was observed at the end of the distillation). A residue of 860g. of a viscous tar remained. The distillate was then refractionated, separating 715 g. of vinyl salicylate boiling at 72 C.-73 C. at 2.5 mm. pressure, 11 1.5477. Allyl salicylate.-This compound can be. repared by the process described in German Patent 244,208. A better procedure is the ester exchange reaction between methyl salicylate. and allyl alcohol using sodium methylate as the catalyst. In a typical run, 304 g. of methyl salicylate, 500 g. of allyl alcohol and 1 g. or" sodium methylate were heated under a distilling column for 12 /2 hours, removing the methanol as itwa's formed. At the end of this period, 92% of the theoretical amount of methanol had been collected. The excess allyl alcohol was removed from the remaining material by evaporation at 40 mm. pressure on a steam bath, and the residue was disoslved in 500 ml. of diethyl ether. This solution was washed with water, dried and distilled. There was obtained 214 g. of allylsalicylate boiling at 82" C. at.

2 mm. pressure, n 1.5326. In the examples .which follow, the inherent viscosities were determined on solutions of the copolymers at 0.1%

An ethylene/vinyl salicylate copolyertwas prepared as follows: aniemulsion of g. ot-vinyl salicylate in 50 ml.

of water containing 0.6 g. of potassium dihydrogen phosprepared salicylate.

phate, 1.0 g. of technical sodium dodecylsulfate and 0.2

g. of benzoyl peroxide was adjusted to a pH of 6.0 by addition of potasisum hydroxide and charged into a pressure vessel. The vessel was pressured with ethylene, heated to 73 C.-75 C. and the ethylene pressure was adjusted to 950 atmospheres After eight hours of heat- I of polymerizedvinyl salicylate and had an inherent visqsi i EXAMPLE A pressure vessel containing 25 g. of vinyl salicylate, :50 ml. of benzene and 0.2 ml. ofdi(tert.-butyl)-p eroxide was pressured with ethylene andheld at an ethylene pressure of 900-950 atmospheres and a temperature of 135 C. for eight-hours with agitation. The resulting ethylstrength of 3540 lbs/sq. in, a break elongation of teasers $6 ene/vinylsalicylate copolymer .(54 g.), after steam distillation and extraction with acetone, was a homogeneous White sponge of inherent viscosity 1.51. It contained 13% of polymerized vinyl salicylate. Films prepared from this copolyrner by's olvent casting or melt pressing at 220 C. were clear, tough and had a zero strength temperature of 100 C.

EXAMPLEY In lbs/sq. in. Its dielectric constant was 2.4.

EXAMPLE -rv Example 11 wasrepeated using 50 g. of vinyl salicylate. There was obtained 20 g. of ethylene/vinyl salicylate copolymer as a transparent resin having an inherent viscosity of 0.69 and containing 19% of polymerized vinyl V This copolymer was readily molded or extruded into obiects such as bars or sheets. A cast film was pliable and readily cold drawn. It had a tenacity of 1580 lbs/sq. in. at 730% elongation.

EXAMPLE V Using the procedure of Example H with 50 g. of vinyl salicylate, 100 ml. of benzene and'0.2 ml. of di(tert.- butyl)peroxide, there was obtained 48 g. of ethylene/vinyl salicylate copolymer as a transparent resin having an inherent viscosity of 1.62 and containing 26% of polymerized vinyl salicylate. This polymer was converted to clear, tough, pliable, films by hot pressing or solvent casting. A film soprepared melted at 0, had a tensile 54% and an initial modulus of 1570.

EXAMPLE v1" A pressure vessel containing 50 g. of vinyl salicylate,.

ml. of chlorobenzene and 0.4 ml. of di(tert.-butyl)- peroxide was pressured with ethylene and held at an ethylene pressure of 600-650 atmospheres and at a temperature of C. for four'hours with agitation. The resulting ethylene/vinyl salicylate copolymer (15 g.) after steam distillation and extraction with acetone was a transparent resin of inherent viscosity 0.51. It' contained 35 of polymerized vinyl salicylate. This polymer could. be converted to apliant film by hot pressing.

EXAMPLE .1

A ternary copolymer of ethylene, vinyl salicylate and and vinyl acetate was prepared as follows: A pressure vessel was charged with 20 g. of vinyl salicylate, 20 g. of vinyl acetate, 50 ml. of benzene and 0.2 ml. di(tert.- butyDpero'Xide, closed, heated to C. and pressured with ethylene to 900-950 atmospheres pressure. The

vessel was maintained at that temperature and pressure for eight hours with agitation. The resulting'polymer was steam distilled and extracted with acetone. obtained 41 g. of a transparent resin, having an inherent viscosity of'1.29. T his was a ternary copolymer containing, by weight, 82% of polymerized ethylene, 10% of vinyl salicylateand 8% of vinyl acetate. Films of this composition pressed at 115 C. were clear and tough.

EXAMPLE VH1 A pressure vessel containing 20 g. of vinyl salicylate,

'20 g. of vinyl acetate, 50 ml. of tert.-.butyl alcohol and 0.2 g. of og, x-azodiisobutyronitrile was pressured with ethylene to-500 atmospheres at 70 C. andheld at that temperature and pressure for eight hours with agitation.

The reaction product after steam distillation and acetone A self-supporting film of this There was extraction consisted of 15 g. of a transparent resin having an inherent viscosity of 0.51; This was a ternary copolymer of ethylene, vinyl salicylate and vinyl acetate containing 11% of polymerized vinyl salicylate and 17% of polymerized vinyl acetate. Pliable self-supporting films were obtained from this copolymer by pressing at 175 C.

EXAMPLE IX An ethylene/allyl salicylate copolymer was prepared as follows: A pressure vessel was charged with 25 g. of

allyl salicylate, 50 ml. of benzene and 0.2 ml. di(tert.- butyl)-peroxide. The vessel was pressured to 900 atmospheres with ethylene at 135 C. and maintained with agitation at that temperature and pressure for four hours. The resulting polymer was steamed and extracted with acetone. There was obtained 68 g. of a transparent copolymer of ethylene and allyl salicylate having an inherent viscosity of 0.64 and containing 14% of polymerized allyl salicylate.

EXAMPLE X A ternary copolymer of ethylene, allyl salicylate and vinyl acetate was prepared as follows: A pressure vessel containing 12 g. of allyl salicylate, 12 g. of vinyl acetate, 50 ml. of benzene and 0.2 ml. of di(tert.-butyl)peroxide was pressured with ethylene to 950 atmospheres at 135 C. The vessel was held at that temperature with agitation for eight hours without repressuring. There was obtained after steam distillation and acetone extraction 42 g. of a ternary copolymer (inherent viscosity 0.43) of ethylene, allyl salicylate and vinyl acetate. This copolymer containing of polymerizedallyl salicylate and 9% of polymerized vinyl acetate. It gave pliable films by pressing at 175 C.

EXAMPLE )Q A casting solution was prepared from 15 g. of the ethylene/vinyl salicylate copolymer of Examplev III (containing 5.5% of vinyl salicylate), 0.39 g. of tris(acetylacetono)-aluminum (sufiicient to chelate 75% of the chelating groups in the polymer), 120 ml. of xylene and 15 m1. of acetylacetone, the latter being added to prevent premature gelation of the crosslinked chelate polymer. Since the ethylene/vinyl salicylate copolymers are not soluble in cold xylene, but are soluble in xylene at temperatures above about 70 C., this soluttion was cast, at a temperature of 105 C., on a nickel plate heated to 90 C., giving a homogeneous viscous film. The solvent and volatile chelating agents were evaporated at 90 C., and the resulting film heated at 125 C. for one hour to complete the transchelation. There remained a strippable, 3-mil thick film of ethylene/vinyl salicylate copolymer crosslinked through the chelate rings formed by the aluminum and the salicylate groups. This film, which contained 0.22% aluminum (0.008 g. atom/100 g.) was insoluble in boiling xylene, although somewhat swollen by it. It had a break elongation of 780% and a tenacity of 2400 lbs./sq. in. It remained pliable at temperatures as low as -72 C., did not melt at 160 C. and was heat sealable at 190 C. When coated onto a steel plate, the bond showed good adhesion.

The table below summarizes some of the film properties of this chelated polymer as compared with the corresponding properties of a film of comparable thickness of the original (unchelated) ethylene/vinyl salicylate copolymer.

, s EXAMPLE xn A hot casting solution was prepared from 10.3 g. of an ethylene/vinyl salicylate copolymer containing 13% of vinyl salicylate, 1.01 g. of tris(ethyl acetoacetato)-aluminum chelate equivalence), 10 ml. of acetylacetone and 90 ml. of xylene. This was cast on a nickel plate heated to 90 C., then heated at 125 C. to evaporate solvent and volatile chelating agents and complete the chelate exchange. There was left a colorless, transparent, tough self-supporting film of ethylene/vinyl salicylate copolymer crosslinked through aluminum chelate rings. This film, which contained 0.63% aluminum (0.023 gram atom per g. of polymer) was insoluble in boiling xylene, and still retained significant strength at 185 C., as compared with a softening point of 100 C. for the non-chelated copolymer. Other film properties included a tenacity of 3500 lbs/sq. in., a break elongated of 290% and an initial modulus of 7000. Such films are heat scalable at 230 C. to give homogeneous bonding. They can be drawn in one direction at temperatures of 90 C.135 C. to give products with lower elongation and much higher tenacity and modulus.

EXAMPLE XIII A casting solution was prepared from 15 g. of the ethylene/vinyl salicylate copolymer of Example 11, 2.02 g. of bis(butylacetoacetato)copper II (90% chelate equiv-, alence), ml. xylene and a 5 ml. excess of butyl acetoacetate. A film was cast and baked as in Example XI; There was obtained a tough, homogeneous green film of ethylene/vinyl salicylate crosslinked through copper che late rings. This product contained 2.2% of copper (0.034. gram atom per 100g. of polymer). The film had a' tenacity of 4040 lbs./sq. in., a breakelongation of 425% and an initial modulus of 11,600. The polymer was in.-'.' soluble in boiling xylene. It showed substantially no deterioration after 500 hours of exposure to ultraviolet light.

EXAMPLE XIV A hot casting solution was prepared from 8.96 g. ofan ethylene/vinyl salicylate copolymer containing 18.3%v

of vinyl salicylate, 65 ml. of xylene, 5 ml. of acetylacetone and 0.90 g. (75% chelate equivalence) of tetrakis. (acetylacetono)zirconium. This solution was cast and cured as described in Example XI. There was obtained a clear, tough film of ethylene/vinyl salicylate copolymer crosslinked through zirconium chelate rings. This film, which was insoluble in boiling xylene, contained 1.9% zirconium (0.021 g. atom/100 g.). It showed no substantial deterioration after immersion in boiling water for 30 minutes. The table below shows some of the film properties of this chelated polymer as'compared with the corresponding properties of the original, unchelated polymer.

EXAMPLE XV The ternary ethylene/vinyl salicylate/vinyl acetate copolymer of Example VII was used to prepare a chelate crosslinked polymer as follows: A hot (105 C.) casting solution was prepared from 16.4 g. of the ternary copolymer, ml. of xylene, 5 ml. of acetylacetone and 0.70 g. (75% chelate equivalence) of tris(acetylacetono) aluminum. This solution was cast and cured as in Ex-' contained 0.009 and 0.040 g.

a ample XI to give a. clear, toughfilm, insoluble in boiling xylene, of copolymer. cross-linked through aluminum chelate ring. A sample of the casting composition de posited on steel showed good adhesion to. the metal. The chelated polymer contained, 0.35% aluminum (0.013 g. atom per 100 -g.).

1 EXAMPLE XVI Hot casting solutions were prepared as follows:

Ethylene/vinyl salicylate copolymer of 18% vinyl salicylate content, gm 9.15 9. Xylene, ml 85 Acetylacetone, m1 2 Butyl acetoacetate, ml 0 .1

bis(Bntyl acetoacetatomickel gm the chelate equivalence of the nickel compound employed being"1-8% and 75%, respectively, based on the copolymer. These solutions were-cast and cured as in Example XI. The resulting films were tough, clear with a pale green coloration. The properties of these films, which atoms of metal/100 g., are

tabulated below:

Polymer Polymer chelated chelated with 16% with 75% equivaequivalence lence nickel nickel Zero strength temperature, C v 220 250 Tensile strength, lbs/sq. in 3, 780 4, 150 Break elongation, percent. 445 220 drlnln's l I 5,100 5, 600

H )hUINOUI The resulting tough, transparent its strength at 145 C. It had a tenacity of 2890 lbs./ sq.

in., a break elongation of 350% and an initial modulus 611.2790 r I EXAMPLE XVIII V A casting solutionwas prepared from 12.8 g. of an ethylene/vinyl salicylate copolymer containing 26% of vinylsalicylate (the product ofExample V), 1.62 g. of

tr'is(acetylacetono)aluminum, 5 ml. of acetylacetone and.

ml. of xylene. The hot solution C.) was cast on a nickel plate as in Example XI. The resulting chelate crosslinked film, which I contained 1.05% aluminum (0.039 g. atom of metal/100 g. of polymer) was clear, strong and pliant with low elongation. The following tablesummarizes some of its properties in comparison with those of theunchelated polymer.

Unchelated Chelated Polymer Polymer Cold crack, C 70 70 Zero strengthtemnerature, C 95 270 Tensile strength, lbs/sq. in 3, 540 3, 800 Break elongation, percent. 540 150 Initial modulus 1, 570 4, 190

10 EXAMPLE XIX A hot casting solution was prepared from 13.1 g. of the ethylene/allyl salicylate copolymer of Example IX, 081g. of tris(acetylacetono)aluminum, 5 ml. of acetylacetone and 95 ml. of xylene. This was cast on a metal plate heated to 90 C. After evaporation of the solvent, the volatile ligand was removed by heating at C. for one hour. The properties oi the cured product and of an unchelated control film are summarized below.

Unchelated Chelated Polymer Polymer Zero strength temperature, C 75 170 Break elongation, percent 160. 180 Tensile strength, lbs/sq. in 830 090 Initial modulus 6, 540 5, 870

EXAMPLE XX A hot castingsolution was prepared from 16.4 g. of theethylene/allyl salicylate/vinyl acetate copolymerof Example X, 1 00 ml. of xylene, 5 ml. of acetylacetone and 0.81 g. (75% chelate equivalence) of tris.(acetylacetono)- aluminum. The solution was cast as in Example XI. The resulting self-supporting film, which contained 0.43% aluminum (0.015 g. atom/100 g. of polymer) was brilliantly clear. The table below lists some of its properties compared with those of theunchelated film.

Unchelated Ohelated Polymer Polymer Cold crack, C 0 -73 Zero strength tem erature, C- 70 Tensile strength, lbs/sq. in. G00 4 1, 500 Break elongation, percent 255 410 Initial modulus 3, 700 5, 800

EXAMPLE XXI This example illustrates chelation by the alcohol exchange method. A mixture of 31 g. of an ethylene/vinyl salicylate copolymer containing 16% of vinyl salicylate and 1.02 g. of aluminum isopropoxide was blended on J heated 'rolls at a temperature in the range of 100 C.-

180 C; This amount of aluminum isopropoxide was equivalent to 50% of the salicylategroups and corresponded to 0.016 g. atom of aluminum per 100 g. of the final polymer. There was obtained, with simultaneous evaporation of the isopropyl alcohol, a tough sheet of chelate crosslinked polymer, from which a pliable film was 'pressed at 260 C. This film did not melt below 1 C. and was insolublein hot xylene. 55

The following examples illustrate the formation of shaped objects other than thin films from the chelate crosslinked polymers of this invention.

EXAMPLE XXII A mixture of 47 g. of an ethylene/vinyl salicylate containing 13.6% vinyl salicylate and 2.09 g. (50% V chelate equivalence) of tris(acetylaceton0)aluminum was charged into a screw extruder heated to 125 C. About .1 ml. of acetylacetone, was added and' the mixture was extruded as a monofilament. The extrudate was cut and repassed successively through the extruder at 150 C., 200 C., and 210 C. to give a fused, rubbery monofilarnent of chelate crosslinked polymer. Curing was completed by heating the filament under tension in a vacuum oven at 150 C. for one hour, giving a rubbery monofil completely insoluble in boiling xylene.

EXAMPLE XXIII A mixture of 163 g. of an ethylene/vinyl salicylate copolymer containing 12% vinyl salicylate, 9, g. (75% apparatus for 8 hours and dried again.

. 11 chelate equivalence) of tris(acetylacetono)aluminum, 15 g. of acetylacetone and 150 g. of cyclohexanone was blended in a closed mechanical mixer at 100 C. The resulting gum was worked on a rubber mill heated to 180 C. This caused evaporation of the volatile chelating agent and of the solvent and gave a translucent sheet, 0.25 inch thick, of chelate crosslinked polymer. This sheet could be molded or extruded readily at 200 C.- 225 C. Thus, a bar x 0.5" x 0.25" was molded at 200 C. and 500 lbs/sq. in. pressure. In an extrusion mold having an orifice 0.315" in diameter, the chelated polymer had a melt index at 220 C. of 10.2 g. per minutes at a loading of 4753 g. A 6 mil thick film pressed from this polymer at 225 C. had a tenacity of 2500 lbs/sq. in., a break elongation of 720% and an initial modulus of 4970. It was still tough and without brittleness at -70 C.

EXAMPLE XXIV pressedinto soft, transparent films at 210 C, These films were insoluble in hot xylene and were not brittle at C. The tensile strength was 3600 lbs/sq. in. at

460% elongation and the initial modulus was -1775, indi eating a highly pliable product.

The copolymers obtained by the methods described in the preceding examplejs'contain substantial quantities of the salicylic ester.

smaller quantities of the salicylic ester, as low as 0.05% by weight. The following examples illustrate the preparation of copolymers which contain a low proportion of the salicylic ester.

EXAMPLE XXV A pressure vessel of 400 ml. capacity was charged with 100 ml. of thiophene-free benzene, 0.15 mol of di(tert.-butyl)peroxide and 2 g. of vinyl salicylate. The vessel was chilled, evacuated to remove air and placed in a shaking apparatus. The temperature was raised to 150 C. during minutes and ethylene was introduced gradually-over a period of 1.5 hours until a pressure of 900 atmospheres was reached. The reaction-was maintained at a temperature range of 128-142 C. and a pressure of 800-900 atmospheres for 2.5 hours. The reaction vessel was then cooled, the pressure was released and the polymeric product was free from solvent and unreacted material by steam distillation. The solid copolymer was dried, extracted with acetone in a Soxhlet There was obtained 27 g. of a solid copolymer which was shown by infrared analysis to contain about 1% vinyl. salicylate. It had an inherent viscosity of 5.1.

EXAMPLE XXVI Using the procedure described in Example XXV a mixture of 4.0 g. of vinyl salicylate and 0.2 ml. of di(tert.-butyl) peroxide in 100 ml. of thiophene-free benzene was heated under ethylene at a pressure of 800-900 atmospheres for 4 hours. tained at 132140 C. except for a brief period at the end of the reaction when the temperature rose to 182 C. There was obtained 52 g. of ethylene/vinyl salicylate copolymer which was shown by infrared analysis to contain about 1.5% of vinyl salicylate. The copolymer had an intrinsic viscosity of 3.54.

The methods arebroadly applicable to--thepreparationof copolymers containing much- The temperature was main-5 12 EXAMPLE xxvn Using the procedure described in Example XXV, av mixture of 2.5 g. of allyl salicylate and 0.2 ml. of di- (tert.-butyl)peroxide in 100 ml. of thiophene-free benzene was heated to 135 C. and ethylene was introduced over a period of 2.25 hours to produce a pressure of 700 atmospheres. The temperature rose to 175 C. at this point and the reaction vessel was cooled with a compressed air stream until the temperature dropped to 140 C. The reaction was then maintained at 135 C. for 1.5 hours under an ethylene pressure of 900 atmospheres. When the reaction mixture was treated as described in Example XXV there was obtained an ethylene/allyl salicylate copolymer which contained, as calculated from the saponification number, 2.5% of allyl salicylate.-

EXAMPLE XXVIII Using the procedure described in Example XXV, a mixture of 5.0 g. of allyl salicylate and 0.2 ml. of di- (tert.-butyl)peroxide in 100 ml. of thiophene-free ben-T zene was heated at 135-146 C. for about 16 hours un: der an ethylene pressure of 850-900 atmospheres. There was obtained 46 g. of ethylene/allyl salicylate copolymer;

1 which contained, as calculated from the saponification number, 3.6% of allyl salicylate. The inherent viscosity of the copolymer was 3.27.

Ethylene/allyl salicylate copolymers which contain 1.4, 1.51 and. 16% of allyl salicylate have been prepared by methods which are similar to those described in the p e edin ie inp s Films of the copolymers which contain as. littleas. 1% of the salicylatecomponent have surprising resistance todeg'radation. by light, as shown in the" tests described 1 in the following paragraphs.

. FS20T12) in a box, the distance from the lamps to the strips being 2 /2. A reflector was placed behind each' lamp. The temperature in the box was about '45": C.: The positions of the film strips in the box were changed. at regular intervals to assure uniform exposure of eachstrip' to the light source. Each strip was tested manually,

for tear-resistance and the film strip was judged to havev failed when it showed low elongation and tore readily; when pulled. The elapsed hours before failure for each; of the copolymers and for a control commercial polyethylene are as follows:

-- Copolymer Hrs. to Failure Ethylene/vinyl salicylate (1%) (Example XXV) 650 Ethylene/vinyl salicylate (1.5%) (Example XX V I) 480 Ethylene/allyl salicylate (2.5%) (Example XXVII).-. 75G Ethylene/allyl salcylate (3.6%) (Example XXVIII) G50 Polyethylene-Control 280 ethylene (also blended with 0.1% of the antioxidant) was prepared in the same manner. Films of the blended. compositions were exposed in an Atlas Weather-Omcter to filtered light with wet and dry cycles.

tear strength (see A.S.T.M. Method Dl004 49T). The

The rate of degradation of each film was followed by determining the superior stability of films of the copolymer over filinsof unmodified polyethylene is shown in the followingtable:

Atlas Weather-Ometer tests At start.

After 500 hours 154. After 1,CO hours 26 After 1,500 hours The control polyethylene was brittle after 500 hours whereas the copolymer retained toughness after 1500 hours.

Thecopolymers of the invention, as described above, possess superior resistance to'degradation by light. This valuable property is particularly evident in copolymers which contain 1% or more of the salicyclic ester. However, the copolymers of this invention have a second valuable property, i.e., the property of screening out deleterious light rays in .the wavelength range of about 230 to 360 millimicronsJ-This property is shown by films of copolymers which have a much lower content of salicyclic ester.

The property of screeningout ultraviolet light, principally, in the region of 310 millimicrons, is particularly. valuablein applications such asbottles, covers for dis: play cases and the like. In. applications of this kind where the ultraviolet screening effect is of primary value, and weathering characteristics are of secondary value, copolymers can be employed which contain only minor amounts of sa'licyclic ester, as little as 0.05 by weight. For example, a copolymer of 99.95% ethylene and 0.051% vinyl salicylate and a copolymer of 99.95% ethylene and 0.05 allyl salicylate are prepared by methods described earlier and the copolymers are formed into sheets'of about mils thickness. Sheets of these co.-'

polymers, which contain only 0.05% of the salicylic ester, absorb almost 100% of light in the region of 310- weightof the, salicylic ester.

they glack thepliability which is necessary in the polymer,

.priorjt'o chelation, since chelation results in increased stitfness.

for crosslinking by chelation are those which contain,

' by weight of the total polymeric composition, from about 7 3% to about 50% of polymerized vinyl salicylate or allyl salicylate. The best balance of film-forming and chelating properties is found in the range of from about 5% to about of polymerized salicylic ester. The ethylene/vinyl salicylate copolymers are preferred over the ethylene/allyl salicylate copolymers because of their outstanding value for the preparation of shaped structures having superior physical properties.

' The chelate crosslinking procedure, although preferably applied to copolymers with 3% by weight or more ofth'e' salicylic ester, can, of course, be applied to all of the copolymers, even copolymers with small amounts of the salicylic ester. As noted earlier, the physical properties, such as toughness, flexibility, and the like, of copolycopolymers which contain minor amounts of the salicylic ester can be shaped into containers opaque to ultraviolet lightsu c h as bottles, whichare useful for storing light-sensitive liquids or. powders. Copolymers used for this purpose are, of course, not limited to compositions which contain 0.05 of thesalicylic ester. copolymers which contain, for example, 0.1%, 0.2% or 0.5%,.of

. vinyl salicylate or allyl salicylate, can be employed, parcopolymers are preferred which contain at least 50% weight of ethylene and about 1-50% by weight of vinyl ,salicylate or allyl salicylate. Copolymers of these compositions have a satisfactory combination of physical properties,-ultraviolet screening effect and resistance to degradationby-light.

For applications employing copolymers crosslinked by chelation, copolymers are used which'contain at least 50% by weight of ethylene and preferably 3-50% by mers which contain small quantities of the salicylic ester do not show as great a changeas a result of chelate crosslinking as is shown by the properties of copolymers of higher salicylic ester. content.

The lethylene/vinylor allyl salicylate copolymers can be prepared by known methods of polymerizing vinyl monomers, such as emulsion or solution polymerization, using known polymerization initiators of the free radical producing typesuch as ammonium persulfate, hydrogen peroxide, organic peroxides,- azonitrile's', and the like. Under controlled conditions, itis possible to obtain in a reproducible manner copolymers of varying composition, depending upon the relative proportions of comonorners in the reaction medium. The copolymers are obtained as essentially colorless materials ranging in physical appearance from tough transparent resins to spongy solids. Their homogeneity is improved by extracting the crude product with a suitable solvent such as acetone to remove unpolymerized material and low molecular weight polymers. V

The copolymers of this invention have high molecular weights, as indicated by'their inherent viscosity (de: termined in tetrahydronaphthalene solutions of 0.1% concentration at l25".C.) which normally is at least 0.40. The more useful polymers have inherent viscosities exceeding 0.5, and attaining or even exceeding 1.5..

The copolymers are generallysoluble, either altroom temperature" or at elevated temperature, in a fairly wide variety oforganic solvents including aromatic-hydrocarto form chelates readily are listed' in the book by Mar-f tell and Calvin entitled Chemistry of the Metal Chelate Compounds (Prentice-Hall, Inc., New York, 1952), particularly at p. 182. Preferred examples of metals suitable for chelation with the above-described copolymersarealuminum and zirconium, because their chelates arejcolorless and have particularly good resistance to hydrolysis. Other very suitable metals are zinc, magnesium, and beryllium, whose chelates are also colorless;

ancltitanium, copper, manganese and iron, when colored products are. desired or not objectionable. Still other usefulpolyvalent metalsinclude cobalt, nickel, chromium,

V V With-copolymersicontaining. less'than about.3% by weight of the salicylic esterfth'e" For these reasons, the copolymers preferred assets;

. cadmium, boron, tin, scandium, vanadium, and bismuth.

For the purpose of preparing the chelate crosslinked polymers by transchelation, that is, reaction of the polymeric polyligand with a polyvalent metal chelate of a vvolatile chelating agent, any suitable chelating agent boiling below about 300 C. at 760 mm. will serve. The preferred Ones are those most available and most economical, which are in general the 1,3-diketones, the ,B-ke'toesters and the aromatic whydroxy aldehydes and esters.

Specifically preferred chelating agents are acetylacetone, 3-methyl 2,4-pentanedione, 3-ethyl-2,4-pentanedione, propionylacetone, tritluoroacetylacetone, 2-furoylaeetone, 2'-

thenoylacetone, ethyl acetoacetate, butyl acetoacetate,

salicylaldehyde, methyl salicylate, and the like. Thus, there may be employed for reaction with the copolymers of vinyl salicylate or allyl salicylate with ethylene the fol-f acetato)iron III; tris(acetylacetono)iron III; bis(1,1,1-

tritluoro-la b'enzylacetono)copper II; tris(2-furoyl) acetonolaluminum; and the like.

.As already mentioned, a polymeric polyligand should preferably be treated with sufiicient metal chelate to produce a final polymer containing at least 0.005 gram atom, and preferably from 0.01 to 0.06 gram atom of metal per 100 g. of chelated polymer. In this treatment and in the subsequent evaporation of the volatile chelating agent, no additional solvent is required in many cases, although an additional solvent is often desirable to prov de a solution of convenient viscosity for the purpose of producing shaped articles. The solvent can be any volatile liquid which is substantially'inert towards the two ,eomponents of the mixture or solution. Suitable orgame solvents include aromatic hydrocarbons, e.g., benzene, toluene or the xylenes, aliphatic alcohols, e.g., methanol, ethanol, n-butanol, acyclic or cyclic ethers, e.'g., di-n-butyl ether, tetrahydrofuran, ketones, e.g., methyl isobutyl ketone, cyclohexanone, and the like. The quantlty of solvent is not critical and needs only be sufficient to decrease the viscosity of the composition to a level practical for film casting or similar uses. The mixtures or solutions so obtained are stable towards gelat1on and can be stored for long periods .of time. If

some tendency to precipitation or gelation is noted onmixing the reactants, such tendency can be overcome by adding a slight excess of the volatile ehelating agent, or of a different one having equivalent or greater chelatmg strength, to keep'the chelated polymer in solution.

Shaped structures such as films cast from these compositions become tack-free rapidly upon air-drying, and even more rapidly upon baking, for example, at temperatures of 50 C. to 200 C. for from 15 minutes to two hours. These products consist of molecules of copolymer of vinyl or allyl salicylate with ethylene cross-linked through the slx-membered chelate rings formed by the polyvalent metal and the salicylate groups. The resulting shaped polymers are flexible, toughand resistant to long exposures to air and light.

' For the purpose of preparing chelate crosslinked poly-- rners by the alcohol exchange method, the polyvalent metals, e.g., those listed above. are used as their alcoholates, preferably with volatile alkanols, e.g., with alkanols of one to four carbon atoms.

iron triisopropoxide, magnesium dibutoxide, zinc dimethoxide, copper dipropoxide, and the like; Suflicient metal Thus, there can be used aluminum trimethoxide, zirconium tetraethoxide,

alkoxide is used, in relation to the number of salicylic ester groups present to give a chelated polymer containing the pro-portions of metal specified above. The reaction is essentially irreversible and does not depend on the removal of the alcohol corresponding to the metal alcoholate to go to completion. It can take place at low temperatures, e.g., at room temperature or lower, but is preferably carried out at higher temperatures such as 100 C.200 C. in order to maintain the chelated polymer in a state of plasticity suflieient to shape it into the desired structure. A solvent or reaction medium is not necessary but, if desired, inert solvents such as benzene or toluene can be used.

A modification of this method consists in treating a shaped structure, such as a film, filament or molded article, of the unchelated ethylene/salicylic ester copolytrier-with the polyvalent metal alcoholate, dissolved for: example in the alcohol from which it is formed. In thisprocedure, chelation takes place at least at the surface of the object being treated, and can even take place.-

. or moldings, particularly in applications where solvent resistance and heat resistance are not essential. Specifically, they are useful as wrapping materials for food products such as meat, cheese, fish or poultry, as book covers, flexible wire coatings, fabric coatings, electrical insulation and sponges. Since the salicylate groups absorb ultraviolet light, the copolymers are useful as glass temperature, the ethylene/vinyl salicylate copolymers are well adapted as wrapping materials for use in refrigera-i tors and freezers.

The chelated ethylene/vinyl salicylate and ethylene/ allyl salicylate copolymers are also useful in the form of films, sheets, filaments, coatings and moldings for the same applications listed for the unchelated polymers. However, they have the added advantages of resistance to heat and organic solvents and of enhanced strength. Specific uses for the chelated polymers include can liners, electrical tape, temperature resistant laminates on glass fabric or fiber, useful as moisture-proof, non-deformable electrical insulating materials resistant to high temperatures, insulating materials for use at relatively high temperatures, fabric coatings, flexible materials for use in articles such as bags, hat covers, overshoes, and the like. They are further useful as reinforcement for plastics, as protective coatings for surfaces such as wood, porcelain and especially metals, e.g., refrigerators, autobodies, furniture and the like, and in the manufaeture by molding or extruding of shaped objects such tations are to be understood therefrom. The invention is not limited to the exact details shown and described for obvious modifications will occur to those skilled in the art.

' We claim:

1. A copolymer of ethylene and a salicylate of the class consisting of vinyl and allyl salicylates, said copolymer containing in the polymerized form, by weight, 0.0550% of the salicylate and at least 50% by weight of ethylene,

2. A copolymer of ethylene and a salicylate of the class consisting of vinyl and allyl salicylates, said copolymer containing in the polymerized form, by weight, 1-507 of the salicylate and at least 50% by weight of ethylene. j 3. A copolymer of ethylene and a salicylate of the class consisting of vinyl and allyl salicylates, said copoly mer containing in the polymerized form, by weight, 350% of the salicylate and at least 50% of ethylene.

4. A copolymer of ethylene and a salicylate of the class consisting of vinyl and allyl salicylates, said copolymer containing in the polymerized form, by weight, 535% of the salicylate and at least 50% of ethylene.

5. A copolymer of ethylene and vinyl salicylate containing in the polymerized form, by weight, 545% of the salicylate and at least 50% of ethylene.

.6. A copolymer of ethylene and allyl salicylate containing in the polymerized form, by weight, 545% of the salicylate and at least 5 of ethylene.

7. A copolymer according to claim 1 containing up.

to 20% of a third polymerizable, terminally ethylenically unsaturated vinyl monomer.

. 8. A coating composition comprising a copolymer according to claim 1 in solution in a volatile organic solvent therefor, said copolymer containing up to 20% of a third polymerizable, terminally ethylenically unsaturated vinyl monomer.

9. A polyvalent metal chelate of the copolymer of claim 3 wherein said copolymer is cross-linked through said polyvalent metal present in six-membered chelate rings formed on diiierent polymer chains, said metal being a common member of siad chelate rings, each of said rings having an atom of the polyvalent metal linked to both the carbonylic and phenolic oxygen atoms of a single salicylate ester unit and said copolymer containing between 0.005 and 0.15 gram atom of the metal per 100 grams of polymer weight.

10. A polyvalent metal chelate of the copolymer of claim 4 wherein said copolymer is cross-linked through said polyvalent metal present in six-membered chelate rings formed on different polymer chains, said metal being a common member of said chelate rings, each of said rings having an atom of the polyvalent metal linked to both the carbonylic and phenolic oxygen atoms of a single salicylate ester unit and said copolymer containing between 0.005 and 0.15 gram atom of the metal per 100 grams of polymer weight.

11. A polyvalent metal chelate of the copolymer of claim 5 wherein said copolymer is cross-linked through said polyvalent metal present in six-membered chelate rings formed on diflerent polymer chains, said metal being a common member of said chelate rings, each of said rings having an atom of the polyvalent metal linked to both the carbonylic and phenolic oxygen atoms of a .single salicylate ester unit and said copolymer containing between 0.005 and 0.15 gram atom of the metal per 100 grams of polymer weight.

12. A polyvalent metal chelate of the copolymer of claim 6 wherein said copolymer is cross-linked through said polyvalent metal present in six-membered chelate rings formed on difierent polymer chains, said metal being a common member of said chelate rings, each of said rings having an atom of the polyvalent metal linked to both the carbonylic and phenolic oxygen atoms of a single salicylate ester unit and said copolymer containing between 0.005 and 0.15 gram atom of the metal per 100 grams of polymer weight.

13. An aluminum chelate of the copolymer of claim 2 wherein said copolymer is cross-linked through aluminum present in six-membered rings formed on different polymer chains, the aluminum being a common member of 18 said chelate rings, each of said rings having the aluminum linked to both the carbonylic and phenolic oxygen atoms of a single salicylate ester unit and said copolymer containing between 0.005 and 0.15 gram atom of aluminum per grams of polymer weight.

14. An aluminum chelate of the copolymer of claim 4 wherein said copolymer is cross-linked through aluminum present in six-membered rings formed on dilferent polymer chains, the aluminum being a common member of said chelate rings, each of said rings having the aluminum linked to beth the carbonylic and phenolic oxygen atoms of a single salicylate ester unit and said copolymer containing between 0.005 and 0.15 gram atom of aluminum per 100 grams of polymer weight.

15. An aluminum chelate of the copolymer of claim 5 wherein said copolymer is cross-linked through aluminum present in six-membered rings formed on difierent polymer chains, the aluminum being a common member of said chelate rings, each of said rings having the aluminum linked to both the carbonylic and phenolic oxygen atoms of a single salicylate ester unit and said copolymer containing between 0.005 and 0.15 gram atom of aluminum per 100 grams of polymer weight.

16. An aluminum chelate of the copolymer of claim 6 wherein said copolymer is cross-linked through aluminum present in six-membered rings formed on difierent polymer chains, the aluminum being a common member of said chelate rings, each of said rings havingthe aluminum linked to both the carbonylic and phenolic oxygen atoms of a single salicylate ester unit and said copolymer containing between 0.005 and 0.15 gram atom of aluminum per 100 grams of polymer weight. I

17. A nickel chelate of the copolymer of claim 5 wherein said copolymer is cross-linked through nickel present in six-membered rings formed on different polymer chains, the nickel being a common member of said chelate rings, each of said rings having the nickel linked to both the carbonylic and phenolic oxygen atoms of a single salicylate ester unit and said copolymer containing between 0.005 and 0.15 gram atom of nickel per 100 grams of polymer weight.

18. A zirconium chelate of the copolymer of claim 5 wherein said copolymer is cross-linked through zirconium present in six-membered rings formed on different polymer chains, the zirconium being a common member of said chelate rings, each of said rings having the zirconium linked to both the carbonylic and phenolic oxygen atoms of a single salicylate ester unit and said copolymer containing between 0.005 and 0.15 gram atom of zirconium per 100 grams of polymer weight.

19. A film of the copolymer of claim 1.

20. A film of the chelate of claim 9.

21. A coating composition comprising a copolymer according to claim 1 in solution in a volatile organic solvent therefor.

References Cited in the file of this patent UNITED STATES PATENTS 2,566,537 Schmerling Sept. 4, 1951 2,582,795 Prentiss Ian. 15, 1952 2,710,801 Minsk June 14, 1955 FOREIGN PATENTS I 582,899 Great Britain Dec. 2, 1946 unTTEn STATES PATENT orrlca CERTIFICATE OF CGRRECTION Patent No. 2 933,474 April 19 1960 Carleton '1, Handy et al.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters 3 Patent should read as corrected below. Column 1 "line 4'? for "nonomerimcfl read --0 monomeric 1. column 2,, lines lO to i l, and lines 24?16'Whe lower portion 1 of each formula should appear as shown below instead of as in the patent:

column 4 line 6 for acoholysis" read alcoholysis :3

line 6?. for "contant read constant column 5 line 53, for "copolyer read -copolymer a line 58 for 'potasisum read potassium -31 column 8, line 17 q for "elongated" read elongation column 9,, line 40, for "solicylate" read salicylate column 14 line 5 for "aholut" read about column l5 line 28 for "-benzylacatono read --benzoylacetono same line for "tris(2-=iuroyl) ace" read trieEZ-(furoyl) ace=- column 17 v line 25 for "*siad" read said ---u Signed and sealed this llth day of October 1960.

( SEAL) Attest:

L AXLINE ROBERT To. WATSQN Atteeting Ofiicer Commissioner of Patenta UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 3 x April 19 1960 Carleton T Handy et al. I

t is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 47 for "nonomeric" read monomeric column 2, l1nes lO to I4 and 111165 24; to mthe lower portion of each formula should appear as shown below instead of as in the patent: v

column i line 6 for "acoholysis" read alcoholysis. ---3 line 62, for "content" read constant column 5, line 53, for "copolyer" read copolymer line 58 for "potasisum" read potassium column 8, line l? for "elongated-read elongation column 9 line 40, for "solicylate" read salicylate column 14L line 5 for "abolut" read about column l5 line 28 for "-benzylacetono" read -benz0ylacetono same line for "tris(2-=iuroyl)ace" read trisEZ-(furoyDacecolumn 17 line 25 for "siad" read said I Signed and sealed this llth day of October 1960.

(SEAL) Attest:

KARL AXLINE ROBERT C. WATSON Attesting Oflicer I Commissioner of Patents 

1. A COPOLYMER OF ETHYLENE AND A SALICYLATE OF THE CLASS CONSISTING OF VINYL AND ALLYL SALICYLATES, SAID COPOLYMER CONTAINING IN THE POLYMERIZED FORM, BY WEIGHT, 0.05-50% OF THE SALICYLATE AND AT LEAST 50% BY WEIGHT OF ETHYLENE. 